Pneumatic ash remover



L J. M. WKLLIIAMS 234,7@

PNEUMATIC ASH REMOVER Filed Sept. '7, 1959 @mig y 68) QU) dil till

Patented Mar. 1l?, 1941 John K. Williams, York, Pa. Application September 7, 1939, Serial No. 293,828

4 Claims.

'This invention relates to pneumatic apparatus ior conveying loose granular or pulverous materials and more particularly for removing and conveying ashes from furnaces, stoves or similar devices and depositing them in a receptacle.

'llhe main object of the invention is to provide means for conveying loose or pulverized material, such as dust or ashes, from one point to another vvithout any dust whatever leaking into the' atmosphere from the conveyor system. Specifically it is an object of the invention to remove ashes from the ash pit of a furnace or stove and to convey the ashes to an ash receptacle inside or outside of the building Without any ashes or dust leaking into the atmosphere either Within the building or outside ci the building. .another object of the invention is to provide efcient means for introducing pulverous rnateriai such as ashes into a closed conveyor circuit.

.dn objection to the older pneumatic ash con veyor system is that when employed with a stoker having the usual blower some method must be provided to close the ash conveyor conduit in order to prevent the operation of the draft from being adected. Therefore an important object oi the invention is to provide a pneumatic ash conveyor 'which may be used with stoves or iurnaces Without aiiecting the operation of the draft in any Way.. y

in carrying out iny invention when employed as an ash remover I provide a substantially closed conduit circuit including a ian for driving the air through the circuit, an injector for pulling the ashes into the air stream circulating around the circuit and a settling chamber Where the ashes are caught in a receptacle such as an ash can or storage bin. In addition the circuit may be provided with lters or dust traps Wherever desired, particularly at the outlet of the settling chamber which outlet is connected to the tan whereby the fan handles only clean air `vvhich it drives through the circuit toward the ash intake located in the ash pit of the furnace.

in the drawing:

Figure i is a diagrammatic showing of my ash conveyor system connected With a furnace.

Figure 2 is an enlarged vertical section of the usual ash pit of a furnace, showing my improved device for introducing the ashes into the conveyor circuit.

Figure 3 is a vertical section of one type of ash receptacle or settling chamber showing how the conduits may be associated with the filter cover.

Referring to Figure l, the furnace Ill is shown installed in a room having a Wall I2 through which the conveyor conduit I4 and the return conduit i6 lead to and from an ash receptacle or settling chamber IB which may be an ordinary ash can or a storage bin. The conduit I4 i carries ash laden air .from the sub ash pit i5 of the furnace I0 directly to the receptacle i8 where practically all oi' the ashes are precipitated While the return conduit It carries air from the filter unit I 9 in thetop 20 of the receptacle to the circulating fan 22 which drives the clean air through the high pressure or return conduit 2l to the injector nozzle it, the end of which is spaced from the flared ash receiving mouth 26 ci the discharge or conveyor conduit Il. the

space being provided so as to allow ashes to move into themouth.

When the fan is 'operating it will be seen that the pressure in the load carrying portion of the circuit, i. e.. in the dischargeV line i4 is reduced thereby creating a suction at the space just mentioned With the result that ashes are drawn vinto the mouth 26 and this action is enhanced by the jet of air irom the nozzle 25. One of the advantages oi the system is that the pressure in the portion it oi the circuit which carries the ashladen air is at all times below atmospheric pressure so that there will never be any leakage of dust into the atmosphere iroin the conveyor or from the ash receptacle. The only part oi the circuit from which air may leali into the atmosphere is the high pressure portion between the -fan and thenozzle but the air in this portion is cleaned so that iealtage is not objectionable except iroin the standpoint ci efficiency. The terms high pressure and low pressure are relative and used primarily for convenience, since actually the pressures are usually not greatly different irom atmospheric.

The injector feeder may be located in the ash pit t'i usually provided in the furnace as shown in Figure 2- but l prefer to install the feeder below the suriace oi the floor it as shown in Figure l. When thus installing the feeder or intake below the floor level it is best to provide a substantial ash hopper it. ii grate t4 may be installed over the hopper it so as to prevent large clinlrers or unburned coal from dropping into the feeder which might cause a stoppage; these cinliers and the like may be removed in the ordinary manner or they may Ibe crushed and forced through the grate it. It is best to slope the walls of the sub-pit as shown so that the ashes will gravitate to the mouth 26 of the discharge conduit.

The ash receptacle I8 is preferably located outside the furnace room or better still outside of the house where it may be reached for emptying Without the necessity of entering the, furnace room. The receptacle may be an ash canot ordinary construction but is provided with a removable lter cover 20 in which is secured a removable lter unit I9, preferably made of material such as matted fibers of vegetable or mineral composition. The end -31 of discharge con- .The cover 20 should have an air-tight fit with the can I8 to increase the eilciency of the system and for this reason it is advisable to provide a gasket 39 around the rim of the cover. Although an ash can is shown in'Figure 3 it is to be understood tha a large storage space may be provided in order tA make it unnecessary to remove the ashes except at long intervals and perhaps at the end of the heating season. It is to be understood that the conduits I4, I6, 24 may be of any desired construction for example ordinary sheet metal pipe of the kind commonly used to transmit air but the terminal sections of the conduit between the ash can and the wall I2 are preferably as indicated in Figure 3 of flexible metal hose to facilitate removal of' the cover from the can when emptying ashes. x

Although a fiber filter unit is shown in the drawing it is to be understood that any other type of dust removing device may be employed in the circuit so as to insure clean air being returned to the fan and to the high pressure side of the circuit. If necessary or desirable additional filters such as shown at 40 and 4I (Figure 1) may be inserted in the suction or low pressure portion of the return conduit I6.

After a period of operation the filtering unit I9 when consisting of matted fibers may become clogged with dust. I find that most of the dust may be removed from the filter units by reversing the air flow through the circuit for a short time and for this reason where it is impractical to reverse vthe fan it is desirable to provide crossover connections 43 and 45 with valves 4l and 48 and also valves in the circuit at 5l! and 5I. During normal ash removal operation the valves 5@ and 5I are open while the other two valves are closed but when it is desired to reverse the flow of air' I open thevalves 4l and 48 and close the valves 50 and 5I.

It is best to carry on the filter cleaning operation When the ash receptacle is empty and the reverse of airflow should not extend for over a period of more than a minute or two which is usually suflicient time to remove most of the dust, especially if the filter unit I9 is tapped lightly with a hammer or other instrument to loosen the dust. Where it is found that a longer period of air reversal is necessary then it may be desirable to provide a valved exhaust outlet 54 and a cuto' valve 55 in the conduit I4; during air reversal with this equipment in the system the valve 56 is closed and the door 56 of the ash pit is opened, so as'not to affect the draft. If desired a filtering device may be inserted in the conduit 24 as indicated at 62 to prevent dust from entering the fan during reversal of air flow.

Where it is undesirable to exhaust into the air then a filter by-pass 58 may be provided around the valve 55 and this by-pass should have valves as at 60 and 6I. When the circuit is provided with the by-pass 58 the open exhaust 54 may be omitted. By closing the valve 55 and opening the valves 60 and 6I the reverse air current is filtered in the by-pass and the filter cleaning may be continued as long as desired, it being understood of course that the ash pit door is closed when the by-pass is used instead of the exhaust.

. The air reversal mechanism 43 to 5I, the exhaust connection 64 and the by-pass 58 and valves 55, 60 and 6I are al1 optional as fairly satisfactory results may be obtained by merely tapping on the lid 20 while the fan is stopped, and when this does not remove most of the dust the filter unit I9 may be removed from the lid and renovatedby any known method.

Instead of the by-pass 6U, 6I I find it more convenient in some installations to use a by-pass around the furnace as shown at 64 in Figure 2 and having a valve 65 that is'normally closed but which may be opened when cleaning the filter I9, at which time the valve 66 in the conduit I4 should be closed'. This by-pass and valves 65 and 66 are also optional as other means may be adopted for cleaning the filters Without departing from my invention.

A great advantage of my system is that it does not affect the operation of the furnace whether the furnace be hand fired, with or without a blower or is fired by means of a stoker having the usual blower. My system will operate with any type of air feed used with the furnace whether natural draft, blower or other device.

When my system is' employed in a furnace equipped with'astoker it will be understood, of course, that the intake will be installed in a manner to receive ashes from the retort and it may sometimes be necessary to sink the hopper I5 to one side of the furnace so that the ashes may easily gravitate into the air stream.

I have shown my ash removal and conveyor system associated with a domestic heating plant because it is in such plants that my invention will probably have its greatest use but my invention is not limited to any size or type of solid fuel burner and is adapted for use in all plants wheret er ash removal is necessary.

What I claim is:

l. The combination in a device for removing ashes from a dwelling stove or furnace; of an ash pit having an exit opening, an air injector nozzle spaced from and discharging into said ash4 pit opening, an ash receptacle having 'a removable cover, a blower conduit discharging high pressure air to said nozzle and withdrawing low pressure `air from the cover, filter means in said cover between the major portion of the receptacle and the withdrawing end of the conduit, and an intermediate pressure conduit conveying ashes from said exit opening through said cover to the receptacle.

2. The device of claim 1 including air reversing means for driving dust out of said lter means and means for short-circuiting the nozzle and the exit opening during reversal of air flow.

3. An ash receptacle cover substantially filled with ash filtering material, an exhaust pipe located horizontally between the cover and the ltering material, a discharge pipe projecting vertically and centrally from the cover on its open side, and a flexible connection to each of said pipes proximate the side edge of the cover to facilitate movement of the cover with respect to the ash receptacle which it covers.

4. In combination, an ash pit having an exit 

